Total phenolic content and antioxidant capacity of former food products intended as alternative feed ingredients

Abstract

The application of Former Food Products (FFPs) as feed ingredients is already documented in swine, as well as their beneficial nutritional value. To date, FFPs extra-nutritional bioactive effect in feed has not been elucidated. Therefore, the aim of the present study was to investigate and compare the total phenolic content and antioxidant capacity (AOC) in six samples of FFPs extracted by different solvent systems. After methanol and acetone extraction, total phenolic content and AOC were determined in FFPs and wheat sample (CTR) using Folin–Ciocalteu and 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonic acid)-ABTS assay, respectively. Results demonstrated that FFPs samples were characterised by an average amount of total phenolic content of 129.3 ± 15.1 mg tannic acid equivalents (TAE)/100g in methanol extracts and 156.4 ± 25.8 mg TAE/100g in acetone extracts. Whereas, the ABTS assay revealed that FFPs showed also anAOC of 138.0 ± 14.3 mg Trolox Equivalent (TE)/100 g in methanol extracts and 173.3 ± 18.8 mg TE/100 g in acetone extracts. Former Food Products represent relevant sources of phenols and antioxidant compounds, which can be beneficial for animal health. Highlights Former Food Products (FFPs) reprocessing is a way to convert food losses into ingredients for animal diets; Valuable content of total phenolic compounds and notable antioxidant capacity were observed in FFPs after extraction with methanol and acetone; FFPs demonstrated to be a source of bioactive compounds with extra-nutritional activities which can be beneficial for animal health.